Antirefill safety valve

ABSTRACT

A valve for pressure systems having a spring-urged sealing member attached to a threaded handle in which handle movement is controlled by means of a stop after filling of the pressure system which limits retrograde movement of the handle sufficiently to avoid mechanical opening of the sealing member. Sufficient handle movement is retained to reduce the spring bias against the sealing member to below system pressure so that the sealing member is hydraulically opened by that pressure until discharge of system contents and pressure, whereupon the sealing member is spring-closed and cannot be reopened.

United States Patent 72 Inventor William Wagner 1 References Cited MiamiBeach, Fla. (c/o Watsco, lnc., 1800 UNITED STATES PATENTS m A l N 3- '33310) 2,077,210 4/1937 Brushe 220/86 o. E22] Fiie d June 3, 1969 PrimaryExaminerM. Cary Nelson [45] Patented Jan. 5, 1971AssirtantExaminer-William B. Wright Attorney-John Cyril Malloy ABSTRACT:A valve for pressure systems having a springurged sealing memberattached to a threaded handle in which handle movement is controlled bymeans of a stop after filling [54] :ALVE of the pressure system whichlimits retrograde movement of a g the handle sufficiently to avoidmechanical opening of the [52] U-S- 137/523, sealing member. Sufficienthandle movement is retained to 2 137/3841 reduce the spring bias againstthe sealing member to below [5|] Int. F16k35/00 system pressure so thatthe sealing member is hydraulically [50] Fkld of Search 137/523, openedby that pressure until discharge of system contents and 3 pressure,whereupon the sealing member is spring-closed and 220/ 6; 2 cannot bereopened.

PATENTEDJAN 5mm f V 3.5521432 SHEET 1 UF 2 INVENTOR. WILLIAM WA 5 5 BYjm 41/41 A TTORNEYS 1 ANTIREFILL SAFETY VALVE BACKGROUND OF THEINVENTION 1. Field of the Invention Single-use valves for pressuresystems.

2. Description of the Prior Art 1 Prior hereto, no valve for pressuresystems known to applicant has permitted filling of the pressure system,permitted selective emptying or discharging of the pressure system andprohibited refilling of the pressure system.

SUMMARY OF THE INVENTION Pressure tanks or other vessels are usuallyfilled under carefully controlled conditions at a charging station andthen distributed to various places for use. When empty it is intendedthat the vessel be returned to the charging center for appropriate reuseor destruction in the case of single use containers. Unfortunately, theattractive economies of refilling containers at points of use orotherwise repressurizing them under less than carefully supervisedconditions has resulted, in the less consequential cases, inintroduction of impurities or inferior refills and, in thevmoreconsequential cases, to injurious explosions. The need has long beenfelt for a valve which would allow normal filling of the pressure vesselunder proper conditions, adequate sealing of the pressure vessel duringnonuse and effective prevention of improper and unauthorized refillingof the vessel together with evidence of tampering. I

Accordingly, the present invention provides a safety valve for pressuresystems in which a spring-urged first sealing member is mechanicallyopened by handle movement to allow filling of the system after whichhandle movement mechanically closes the first sealing member. Handlemovement is now reduced in extent by a stop such as a valve-top collar.

Withdrawing the handle to its full limited extent is insufficient tomechanically open the first sealing member but does permit hydraulicopening thereof by system pressure for system emptying. When the systempressure is lowered to a level insufficient to overcome the spring bias,first sealing member is spring-closed and cannot be reopened due to thelimited handle travel. v

The valve of the present invention provides two notable safety featuresin addition to the antirefilling function. The first is the nature ofthe stop which limits handle travel; in a preferred form of theinvention the stop is a formable collar at the top of the valve aboutthe handle stem to engage an enlargement on the stem. Tampering with thevalve to permit refilling of the pressure system would leave its clearlyvisible mark in the form of a damaged collar thereby warning prospectiveusers of the system and giving notice of the vandalism. Second, anotherspring-urged sealing member is provided as a relief for excessive systempressure. This safety valve functions independently of the primarysealing member.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary view of the topof the pressure vessel showing the valve of the present inventionmounted thereon between a pair of handles or guards. I

FIG. 2 is a cross-sectional view of the valve of the present inventionas taken across line 2-2 of FIG. 1.

FIG. 3 is a cross-sectional view taken across line 3-3 of FIG. 2.

FIG. 4 is a cross-sectional view taken across line 4-4 of FIG. 2.

FIG. 5 is a side view of the handle, handle stem and primary sealingmember of the valve of the present invention.

FIG. 6 is a fragmentary cross-sectional view of the lower portion of amodified form of the handle stem and primary sealing member.

FIGS. 7--1I show the valve of the present invention in various operatingpositions in fragmentary cross-sectional view. FIG. 7 shows the valve inits filling position in which the ban dle is fully withdrawn togetherwith the primary sealing member for purposes of filling the pressurevessel. FIG. 8 shows the valve in its closed position with the collarformed about the handle stem. The locked position of the lower portionof the valve stem is shown in phantom. FIG. 9 shows the valve in itsdischarging position in which the handle is partially withdrawn, theprimary sealing member hydraulically opened. FIG. 10 shows the valve inits closed position with the safety element open. FIG. 11 shows thevalve with the handle fully withdrawn to the limit of the collar stopbut with the sealing member closed to prevent refilling of the vessel.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Pressure vessel orpressure system 10 is provided with antirefill safety valve 12 forfilling and selective emptying of the vessel. ,Valve 12 may be welded tothe vessel between the a pair of guards I4 which may also serve aslifting handles. Valve 12 is provided with a housing 16 having a centralbore 18 communicating with the interior of vessel 10 and a side port 20communicating with the bore. A handle 22 having a hollow stem 24 is inthreaded engagement with the upper portion of bore 18. The top ofhousing 16 is provided with a formable flange 26. The lower portion ofstem 24 is provided with an annular extension 28 about which is securedthe upper end of a compression spring 30 and to which is secured atubular extension 32 extending downwardly to a flared bottom. Ridingtube 32 is primary sealing member 34 which is biased by the lower end ofspring 30 against a seat 36 formed in bore 18. The flare at the end oftube 32-prevents removal of primary sealing member 34. In a modifiedform of the invention as shown in FIG. 6, primary sealing member 34a isan integral lower extension of tube 32a and no flare is necessary exceptas may be used to secure a sealing washer. Either form, tube orextension, constitutes connecting means between the primary sealingmember and the tube for mechanical opening of the sealing member byretrograde movement of the handle. The connecting means is a slide forthe sealing member.

Bore 18, the interior of tube 32 and the interior of hollow stem 24communicate between the interior of vessel 10 and the atmosphere exceptas may be closed by a secondary safety valve located in stem 24. Thesecondary valve comprises a secondary sealing member 40 and is biasedagainst vessel pressure by secondary spring 42 which is located at itsother end by a crossmember 44. Secondary sealing member 40 seals againsta seat 46 formed in stem 24 by a reduction in the bore diameter thereof.

OPERATION OF PREFERRED EMBODIMENTS OF THE INVENTION In order to fillvessel 10, handle 22 is withdrawn sufficiently to permit unseating ofprimary sealing member 34 by longitudinally pulling it away from seat 36by tube 32. See FIG. 7. When the vessel is filled, handle 22 is advanceduntil prirriary sealing member 34 is in sealing contact with seat 36under sufficient pressure of spring 30 to overcome the pressure in thevessel.

If it is desired to firmly lock primary sealing member 34 against thisseat, handle 22 is merely advanced sufficiently to cause annularextension 28 to bear against primary sealing member 34 and hold it insealed position; this is shown by the dotted lines at the bottom of FIG.8.

Flange 26, which until now had permitted unlimited withdrawal of stem 24and handle 22 from housing 16 is now cramped or otherwise formed aboutstem 24 to form collar or stop 26' which engages an enlargement on stem24 to form limit retrograde movement of handle 22 and stem 24 outwardlyof housing 16. For convenience, that enlargement may also be providedwith the threads of the stem.

Handle 22 may now be withdrawn only to the extent shown in FIG. 11; thatis, only until the stop engages the stem enlargement. This full limitedretrograde movement is not sufficient to mechanically raise primarysealing member 34 from seat 36. Sufficient pressure in vessel tohydraulically raise primary sealing member 34 above seat 36 againstspring 30 will permit discharge of vessel contents through port as maybe seen in FIG. 9. There is no way to raise primary sealing member 34short of destruction of the valve in general and stop 26' in particular.

It will accordingly be seen that the valve of the present inventionpermits initial filling of the vessel but, after engagement of stop 26',does not permit refilling of the vessel for the reason that primarysealing member 34 cannot be opened except by pressure internal of thevessel.

When primary sealing member 34 is closed and pressure in the vesselrises to an unsafe extent, secondary sealing member 40 is opened and thepressure allowed to escape to the atmosphere. The critical pressure atwhich secondary sealing member 40 opens is determined by the strength ofsecondary spring 42. Generally speaking, however, it is preferable thatthe strength of spring 30 be greater than that of secondary spring 42when handle 22 is closed as shown in FIG. 10 and that the strength ofspring 30 be less than that of secondary spring 42 when handle 22 isopened to its full limited position as shown in H0. 11. The purpose ofthese relative spring strengths, of course, is to regulate which sealingmember, primary or secondary, is to open and which is not to open underparticular conditions. Thus, when it is desired to empty the contents ofthe vessel through port 20, primary sealing member 34 should open andsecondary sealing member 40 should not, see FIG. 9. On the other hand,automatic venting of unsafe vessel pressure should be through handle 22to the atmosphere and not through port 20 and to whatever system thatport may connect. The proper condition is shown in FlG. 10 wherein thevessel pressure is sufficient to open secondary sealing member 40 butinsufficient to open primary sealing member 34. The variations instrength of spring 30 are determined by the longitudinal position ofhandle 22 whereby spring 30 is compressed to a greater or lesser extent.Of course, when handle 22 is in its locked position such as shown inphantom in FIG. 8, the strength of spring 30 relative to that ofsecondary spring 42 is unimportant for the reason that annular extension28 bears directly against sealing member 34 and locks the latter inclosed position.

Modifications in the foregoing may readily be provided. For

example, the stop necessary to limit retrograde movement of handle 22may be either a continuous or interrupted annular flange.

lclaim:

1. A valve for a pressure system, comprising:

a. a housing providing communication between a port and the pressuresystem for charging and discharging the latter;

b. a handle, including a stem portion, in threaded engagement with saidhousing;

c. a spring-urged sealing member for closing and opening communicationbetween said port and said system, said sealing member being mounted formechanical movement by said handle and for hydraulic movement by systempressure against spring bias; and

d. engageable stop means for limiting retrograde handle movement tobelow that required for mechanical opening of said sealing member.

2. A valve for a pressure system in accordance with claim I, whereinsaid engageable stop means is selectively engageable with said handle.

3. A valve for a pressure system in accordance with claim 1,additionally comprising connecting means to connect between said sealingmember and said handle for mechanical opening of said sealing member bysaid handle.

4. A valve for a pressure system in accordance with claim 3, wherein:

a. said connecting means comprises a slide for said sealing memberjoined at one end to said handle for movement therewith and having anenlargement at its other end to prevent removal of said sealing member;and b. the spring of said sealing member bears outwardly between saidhandle and said sealing member.

5. A valve for a pressure system in accordance with claim I, whereinsaid engageable stop means comprises a formable flange.

6. A valve for a pressure system in accordance with claim 1, whereinsaid engageable stop means comprises a formable extension of saidhousing.

7. A valve for a pressure system in accordance with claim 1, whereinsaid engageable stop means comprises a collar formed about said stem forengagement therewith.

1. A valve for a pressure system, comprising: a. a housing providingcommunication between a port and the pressure system for charging anddischarging the latter; b. a handle, including a stem portion, inthreaded engagement with said housing; c. a spring-urged sealing memberfor closing and opening communication between said port and said system,said sealing member being mounted for mechanical movement by said handleand for hydraulic movement by system pressure against spring bias; andd. engageable stop means fOr limiting retrograde handle movement tobelow that required for mechanical opening of said sealing member.
 2. Avalve for a pressure system in accordance with claim 1, wherein saidengageable stop means is selectively engageable with said handle.
 3. Avalve for a pressure system in accordance with claim 1, additionallycomprising connecting means to connect between said sealing member andsaid handle for mechanical opening of said sealing member by saidhandle.
 4. A valve for a pressure system in accordance with claim 3,wherein: a. said connecting means comprises a slide for said sealingmember joined at one end to said handle for movement therewith andhaving an enlargement at its other end to prevent removal of saidsealing member; and b. the spring of said sealing member bears outwardlybetween said handle and said sealing member.
 5. A valve for a pressuresystem in accordance with claim 1, wherein said engageable stop meanscomprises a formable flange.
 6. A valve for a pressure system inaccordance with claim 1, wherein said engageable stop means comprises aformable extension of said housing.
 7. A valve for a pressure system inaccordance with claim 1, wherein said engageable stop means comprises acollar formed about said stem for engagement therewith.